21537717080 has 64 divisors (see below), whose sum is σ = 53053742880. Its totient is φ = 7803980800.

The previous prime is 21537717079. The next prime is 21537717107. The reversal of 21537717080 is 8071773512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36542 + ... + 210738.

Almost surely, 2^21537717080 is an apocalyptic number.

21537717080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21537717080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26526871440).

21537717080 is an abundant number, since it is smaller than the sum of its proper divisors (31516025800).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21537717080 is a wasteful number, since it uses less digits than its factorization.

21537717080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174500 (or 174496 counting only the distinct ones).

The product of its (nonzero) digits is 82320, while the sum is 41.

The spelling of 21537717080 in words is "twenty-one billion, five hundred thirty-seven million, seven hundred seventeen thousand, eighty".